record-breaking high temperatures. according to a climate assessment commissioned by the city, chicago's annual average temperature has warmed by more than two degrees fahrenheit since 1945. unless something changes this trend line, by the end of the century a chicago summer could feel like an atlanta, georgia, summer, and there could be more frequent, longer, and more intense heat waves like that of 1995. there also could be more rain, since higher temperatures means less precipitation falls as snow. >> the data there really set the stage for us to think about what solutions could be in place. the data suggested things like we will see more high-heat days, more heat events, more rain, more storm events, in the context of an overall change and some warming. >> sreenivasan: karen weigert is the chief sustainability officer for the city heading up chicago's ambitious mission to cool the city wn. >> we're in the midst of, right now, a $7 billion multi-year program on building a new chicago. so we're redoing and renovating infrastructure throughout the city.